1. Field of the Invention
The present invention relates to a wrench which has unique pairs of inside working surfaces developed to reduce or eliminate slippage and other conventional wrench problems and to provide for surface-to-surface contact instead of point-to-point contact during high torque usage. The present invention wrench may be any of the known types of wrenches including open-end, box-end, adjustable, socket, etc.
2. Prior Art Statement
Various types of wrenches having conventional configurations to conform to the exact shape of nuts, bolts and fasteners with which they are used have, by necessity, tolerances and clearances which create problems when substantial torque is applied to the wrenches. Recent developments in the art have been directed to the reduction of slip and wear of fastener corners by conventional wrenches.
For example, U.S. Pat. No. 3,125,910 issued to Kavalar describes a wrench having at least 10 cylindrical lobes for equalizing torque exertion. U.S. Pat. No. 3,241,409 to Raptis describes a box wrench having a pivotally, slidably disposed torquing element for relative movement of opposite contact surfaces within the wrench opening during application of torque. This device requires substantial manufacturing with moving parts.
U.S. Pat. No. 3,242,775 to Hinkle describes a wrench for engaging nut contact surfaces to inhibit marring. Curved wrench surfaces are utilized for contact surfaces of the wrench head, and angles vary along these contact surfaces to have a first, then a second portion contact the nut sequentially with increased torquing.
U.S. Pat. No. 3,695,124 to Myers describes angular wrench head with arcuated ribs for rounded point contact with fasteners.
Notwithstanding attempts in the prior art to overcome the substantial deficiencies of standard wrenches none of the prior art teaches or renders obvious the improved wrench of the present invention.